Memory device, memory system, and program operation method thereof

A memory system, comprising:

• a memory controller coupled to a memory device and configured to send one or more first instructions corresponding to cold data, the memory device comprising a memory cell array and peripheral circuits coupled to the memory cell array,
• wherein:
• the peripheral circuits are configured to perform twice program operations, in response to the one or more first instructions, on one or more first memory cells in the memory cell array for storing the cold data into the one or more first memory cells, the twice program operations comprising a first time program operation and a second time program operation;
• and
• the twice program operations comprise:
• perform the first time program operation for successfully storing the cold data into the one or more first memory cells;
• and
• upon determining that the first time program operation has been successfully performed on the one or more first memory cells, perform the second time program operation for storing the cold data into the one or more first memory cells, the second time program operation being configured to narrow a threshold voltage distribution, corresponding to a programmed state among the one or more first memory cells, for improving retention characteristics of the cold data.

A memory system, comprising:

• a memory controller coupled to a memory device, and configured to send one or more first instructions corresponding to cold data, and one or more second instructions corresponding to hot data;
• and
• the memory device comprising a memory cell array and peripheral circuits coupled to the memory cell array,
• wherein the peripheral circuits are configured to:
• perform twice program operations, in response to the one or more first instructions, on one or more first memory cells in the memory cell array for storing the cold data into the one or more first memory cells, the twice program operations comprising a first time program operation and a second time program operation, the second time program operation being performed using the cold data on the one or more first memory cells upon a determination of a successful result of the first time program operation for storing the cold data into the one or more first memory cells;
• and
• perform once program operation, in response to the one or more second instructions, on one or more second memory cells in the memory cell array for storing hot data into the one or more second memory cells.

A method for programming data, comprising:

• performing twice program operations on one or more first memory cells in a memory cell array for storing cold data into the one or more first memory cells, the twice program operations comprising a first time program operation and a second time program operation,
• wherein performing the twice program operations comprises:
• performing the first time program operation for successfully storing the cold data into the one or more first memory cells;
• and
• performing the second time program operation for improving retention characteristics of the cold data, wherein:
• the first time program operation comprises a first programming pulse that includes a first initial pulse voltage and a first initial pulse duration, and the second time program operation comprises a second programming pulse that includes a second initial pulse voltage and a second initial pulse duration;
• and
• at least one of the first initial pulse voltage being substantially identical to the second initial pulse voltage or the first initial pulse duration being substantially identical to the second initial pulse duration is satisfied.